1. Field of the Invention
The invention relates to oil well technology. More particularly, the invention relates to a downhole fluid flow and pressure equalization control and choke devices.
2. Prior Art
Flow control has been a concern of the oil drilling industry since the first well produced a gusher like that of spindle top in Texas on Jan. 10, 1901. Initially, flow control was focused upon surface based apparati, however, as technology advanced and multiple production zone/multiple production fluid wells grew in popularity, flow control downhole has become increasingly important.
One particular prior art device which has been very effective is the CM sliding sleeve commercially available from Baker Oil Tools, 6023 Navigation Boulevard, Houston Tex. 77011. The sleeve employs one outer housing with slots and one inner housing with slots. The slots are alignable and misalignable with axial movement of the inner housing relative to the outer housing. The tool is effective for its intended purpose but does not provide any selectivity regarding where on the circumference flow is desired. Other valving and choking devices are also available in the prior art but there is still a need for more efficient devices and specific devices to function where others have not proved effective. Moreover, devices which function with less or no input from the surface are also likely to have a significant positive impact on the industry.
The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the downhole flow control devices of the invention.
In connection with all of the following embodiments and sub embodiments of the invention it will be understood that these include (although could be employed without) downhole electronics including processors, sensors, etc., in the downhole environment which perform decision making tasks based upon input from sensors and or from preprogramming and or from surface input. These intelligent systems are more fully discussed in U.S. Pat. No. 5,597,042 which is assigned to Baker Hughes Incorporated who is the assignee hereof. The entire contents of U.S. Pat. No. 5,597,042 is incorporated hereby by reference.
In the first embodiment of the invention a cylindrical tool having a plurality or multiplicity of individual valve bodies is provided. The valve bodies are individually activatable to meter flow circumferentially around the tool. Among the individual valve bodies, three subembodiments are most preferred. In the first subembodiment each individual valve is arranged to be rotationally adjustable; in the second subembodiment, which is of very similar appearance to the first, the valve is arranged to be adjustable to be longitudinally slidable; and the third subembodiment provides a conical/cylindrical spear valve and a conical/cylindrical mating structure which allows fluid to flow when the spear is not fully urged into the cone.
With all of the subembodiments of the first embodiment of the invention, metered control is possible as well as circumferential control. It will be understood that among the valve bodies, differing subembodiments may be assembled within one tool.
Actuation of the valve bodies of any of the subembodiments maybe by way of electric motor, hydraulic or pneumatic pressurized flow or otherwise. Another feature of the invention is a downhole electronics package that allows for the downhole decision making sensing and powering of the downhole tools of the invention.
In a second embodiment of the invention, a toroidal inflatable/deflatable bladder is disclosed which provides a centrally located orifice through which fluid may flow when the bladder is not fully inflated thus occluding the orifice. An advantage of the device is that it is very versatile and is capable of a great many closing and opening cycles in varying degrees without failure.
In a third embodiment of the invention a dependent sleeve choke mechanism is disclosed. The tool includes inner and outer sleeves which are disposed one on either of the inner and outer diameter of the housing of the tool. The inner and outer sleeves are fixedly connected to one another such that the sleeves move in tandem to conceal or reveal openings in the housing through which fluid may flow. Actuation may be by electric, hydraulic or pneumatic motor and a gear train or can be by conventional shifting tools. Position sensors are preferably employed to provide information regarding the position of the sleeve. Other sensors as disclosed in Baker Oil Tools U.S. Pat. No. 5,597,042 issued Jan. 28, 1997 which is assigned to the assignee hereof and incorporated herein by reference.
In a fourth embodiment of the invention, similar to the third embodiment, an independent sleeve choke mechanism is disclosed. In the independent mechanism, the inner and outer sleeves are not connected to one another and may be actuated independently of one another. Actuation may be by a single motor, solenoid switchable to the desired gear train or may be two motors independent of one another. The sensing or processing as discussed above are applicable to this embodiment as well.
In general, with respect to the above, position sensors such as linear potentiometers, linear voltage displacement transducers (LVDT) resolvers or a synchro is employed to determine position of either the dependent or independent sleeve choke devices. Moreover, in both the third and fourth embodiments, shear out mechanisms are provided in the event of failure of the powered actuation system so that the tool may be conventionally actuated with for example a shifting tool.
In a fifth embodiment of the invention, a nose seal choke mechanism is disclosed. The nose seal choke mechanism includes a moveable sleeve on the inside of a ported housing which regulates flow by obstructing the amount of port area open to flow. Flow is restricted by the unique stepped out nose on the inner sleeve. The mechanism provides an advantage by shielding seals from flow through the device. This is beneficial because it prevents seals being washed out or flow cut during operation of the choke mechanism. The device is actuatable by powered means or, if such means fail, by conventional means after shearing. This device also provides a dual back up operation by adding a second shear out mechanism and a second flow control.
A sixth embodiment of the invention is a helical key choke mechanism. This device includes helical grooves around the O.D. of a ported housing and keys set within the grooves that are moveable based upon the movement of a sleeve which is attached to the keys either directly or through an intermediary. By moving the keys into the helical flow path, flow is restricted; by moving the keys out of the flow path, flow can be increased. Preferably there are a total of four keys used so that the flow area is maximized through the annular area while still promoting accurate and substantial control of fluid. The inner sleeve, to which the keys are operably attached, is actuated by motors of electrical, hydraulic or pneumatic modes of operation or conventionally after shear out of the shear release sleeve.
In a seventh embodiment of the invention, a spiral choke mechanism is disclosed which enlarges or restricts port openings in a ported housing by rotation of a spiral choke device. Rotation of the choke device changes the throat opening between the ported housing and the port in the spiral choke. This enables reliable metering of the flow from the well annulus to the tubing string. Sensors are used to determine the position of the metering spiral choke device. Actuators for the device are similar to those discussed above, and a shear out structure is supplied for removing the powered actuator from contact with the choke device. In this embodiment the shifted operation is a one time permanent closure operation.
An eighth embodiment of the invention is an orifice choke mechanism wherein a moveable sleeve inside an orifice housing having a plurality of hard material orifices regulates fluid flow by obstructing number of orifices open to flow. In this embodiment the entry of the orifices is square edged to provide a pressure drop. The device is preferably actuated by a motor and gear train assembly which includes spur gears and a drive screw. A shear out mechanism is incorporated to allow the sleeve to be conventionally actuated in the event that the powered actuators should fail.